Mechanical multiplier



Aug. 30, 1955 w. c. BROWN 2,715,521

MECHANICAL MULTIPLIER Filed Sept. 8, 1955 3 Sheets-Sheet l Aug. 30, 1955 w. c. BROWN 2,716,521

MECHANICAL MULTIPLIER Filed Sept. 8, 19 5 3 Sheets-Sheet 2 Aug. 30. 1955 w. c. BROWN 2,716;521

MECHANICAL MULTIPLIER Filed Sept. 8, 1953 3 Sheets-Sheet 3 1 A f B 22 C. R D

ruv vr m WILLIAM cRocn' ax wu United States Patent MECHANICAL MUL'llPLIER Wiiliam (I. Brown, Ottawa, Ontario, Canada Application September 8, 1953, Serial No. 379,050

10 Claims. (Cl. 235-61) This invention relates to a new and improved commined mechanical multiplier and divider.

It is an object of the present invention to provide a combined mechanical multiplier and divider in which the input and output scales are linear.

It is also an object of the present invention to provide such a device equally suited to multiplication and division separately or simultaneously.

It is a further object of the present invention to provide a true combined mechanical multiplier and divider unaffected by the time factor as is the case of an integrator and capable of sufficient accuracy for analog devices. Yet another object of the present invention is to provide such a device having a minimum of friction.

According to the present invention a combined mechanical multiplier and divider comprises two rigidly held, parallel, main guide members; two main carriages respectively mounted for movement parallel to one another along each of said main guide members; an input drive means serving to cause said movement of one of said main carriages; said movement of the other of said carriages serving to operate an output drive means; a cross guide member rigidly mounted along a straight line crossing both of said main guide members; a variableratio drive-transmitting member extending across both of said main guide members, slidably pivotally connected to each of said main carriages and pivotally connected to said cross guide member by a pivot member adjustable along the length of said cross guide member; and means for adjusting the position of said pivot member along said cross guide member.

In the accompanying drawings which illustrate the preferred embodiments of the present invention:

Figure 1 is an isometric view of a combined multiplier and divider,

Figure 2 is a modification of Figure 1,

Figure 3 is a diagrammatic plan of Figure 1, and

Figure 4 is a diagrammatic plan of Figure 2.

In Figures 1 and 2, two parallel, main guide bars 1 and 2, respectively formed with longitudinal slots 3 and 4, are rigidly mounted above and parallel to a base plate 5. A cross guide bar 6 formed with a longitudinal slot '7 is rigidly mounted along a straight line crossing both the main guide bars 1 and 2'. While it is not essential that they be so, in the preferred embodiment the cross guide bar 6 is normal to the main guide bars 1 and 2, the main guide bars 1 and 2 are of substantially equal length and they are substantially bisected by the line along which the cross guide bar 6 is lying.

The cross guide bar 6 is also held above and parallel to the base plate but lies in a plane lower than that of the main guide bars 1 and 2.

A short vertical pivot post 8 is slidably located in the longitudinal slot 7, rigidly connected to a U-shaped bracket 9 above the bar 6 and rotatably connected to an inverted U-shaped bracket 10 beneath the bar 6. The bracket 9 is rigidly secured to a variable-ratio, drivetransmitting bar 11, formed with a longitudinal slot 12.

gear Wheels as indicated by the gear 2 ,7 l 6 ,5 Z I Patented Aug. 30, 1 955 The drive-transmitting bar 11 is disposed so as to lie in a plane intermediate the planes in which the cross guide bar 6 and the main guide bars 1 and 2 are lying.

Carriages 13 and 14 are slidably mounted in the longitudinal slot 12, one on either side of the pivot post 8. The carriages 13 and 14 are respectively pivotally con nected to carriages 15 and 16 slidably mounted one in the longitudinal slot 3 and one in the longitudinal slot 4.

A secondary guide bar 17, having formed therein a longitudinal slot 18, is mounted along a line running from a point on the main guide bar 1 to the point at which the cross guide bar 6 crosses beneath the main guide bar 2. The foregoing point on the main guide bar 1 may be at any distance from the point of intersection between the line along which the cross guide bar 6 lies and the main guide bar 1, dependent upon the scale to be employed. For convenience it lies close to the end of the main guide bar 1 in the preferred embodiment. The secondary guide bar 17 is held parallel to the base plate 5 and lies in a plane lower than that of the cross guide bar 6.

A ratio-varying bar 19, having formed therein a longitudinal slot 20, is rigidly secured to the bracket 10 so that it is pivotable in a plane intermediate the planes in which the cross guide bar 6 and the secondary guide bar 17 are lying.

A carriage 21 is slidably mounted in the longitudinal slot 20 on the side of the pivot post 8 nearest the secondary guide bar 17. The carriage 21 is pivotally connected to a carriage 22 slidably mounted in the longitudinal slot 18.

Parallelto and adjacent the secondary guide bar 17, a threaded shaft 23 is rotatably mounted. An internally threaded collar 24 is mounted on and in engagement with the thread of the shaft 23 and is rigidly connected to the underside of the carriage 22. At one end of the shaft 23 a gear wheel 25 is rigidly mounted thereon and co-axially therewith. Suitable drive means may be applied direct to the gear wheel 25 or through a train of wheel 26.

Referring now specifically to Figure 1, the ratio-varying bar 19 is pivoted, on the side of the pivot post 8 remote from the secondary guide bar 17, about a bush 27 which is located in the slot 24) and which is rigidly secured to a block 28 by means of a screw which also serves to retain the ratio-varying bar 19 about the bush 27. The block 28 serves to maintain the bar 19 parallel to the base 5. The bush 27 lies on a line parallel to the secondary guide bar 17 and passing through the point of intersection between the longitudinal axis of the slot 7 in the cross guide bar 6 and the longitudinal axis of the slot 3 in the main guide bar 1. The position of the bush 27 along said line parallel to the secondary guide bar 17, in the preferred embodiment, is fixed at the point where said line is intersected by a line running parallel to and equidistant from the main guide bars 1 and 2. However, the position of the bush 27 along said line parallel to the secondary guide bar 17, may vary according to the desired range of scale values.

In Figure 2, an embodiment is shown where a second secondary guide bar 29 is rigidly held parallel to and in the same plane as the secondary guide bar 17. The second secondary guide bar 29 is formed with a longitudinal slot 30 and lies along a line running from a point on the main guide bar 2 to the point where the longitudinal axis of the slot 3 in main guide bar 1 is intersected by the longitudinal axis of the slot 7 in the cross guide bar 6.

A carriage 31 is slidably mounted in the longitudinal slot 20 on the side of the pivot post 8 remote from the secondary guide bar 17 and is pivotally connected to carriage 32 slidably mounted in the longitudinal slotv 30.

A threaded shaft 33 is mounted for rotation parallel to and adjacent the second secondary guide bar 29 and an internally threaded collar 34 is mounted on and in engagement with the thread of the shaft 33. The collar 34 is rigidly connected to the underside of the carriage 32 as is the collar 24 connected to the carriage 22.

A gear wheel 35 is rigidly mounted on and co-axially with the shaft 32 at the end thereof remote from the gear wheel 25 mounted on the shaft 23. A drive may be applied directly to the gear wheel 35 or through a train of gears as indicated by the gear wheel 36.

In both the preferred embodiments shown in Figures 1 and 2 numerous methods may be used to apply a drive to or take a drive from the carriages 15 and 16. The preferred method of accomplishing this is shown in both Figures 1 and 2.

Bands or cables 37 and 38 are attached respectively to the carriages 3 and 4. The band 37 passes round and is held between pulleys 39 and 40 disposed one at either end of the main guide bar 1 and the band 38 passes round and is held between pulleys 41 and 42 disposed at either end of the main guide bar 2. A gear Wheel 43 is rigidly secured to and co-axially with the pulley 39. A similar gear wheel 44 is rigidly secured to and co-axially with the pulley 42. A drive may be applied to or taken from the carriages 3 and 4 through the gear wheels 43 and 44 and, if required, through trains of gears as indicated at 45 and 46 which may be used to extend the range of variables.

The working of Figure l is illustrated in Figure 3 wherein all lines and other diagrammatically drawn parts corresponding to those in Figure l have been given like numeral references. The lines parallel to the secondary guide bar 17 on which the bush 27 is located is shown in Figure 3 as the dotted line BD.

A paralllelogram ABCD is formed by two diagonally opposed sections of the main guide bars 1 and 2, the secondary guide bar 17 and the line BD. The parallelogram is diagonally bisected by the cross guide bar 6, slidably pivoted to which are the drive-transmitting and the ratio-varying bars 11 and 19.

If the points of intersection between the drive-transmitting bar 11 and the main guide bars 1 and 2 are designated Q and R respectively, if the point of intersection between the drive-transmitting bar 11 and the ratiovarying bar 19 is designated E and if the points of intersection between the ratio-varying bar 19 and the secondary guide bar 17 and the line BD are designated X and Y respectively, it will be seen that similar triangles QEB and CER are formed between the drive-transmitting bar 11 and the cross guide bar 6 and that similar triangles BEY and CEX are formed between the ratio-varying bar 19 and the cross guide bar 6.

It is on a well-known theorem of similar triangles that the present invention is based. According to this theorem,

Thus, if the length CR is considered to be the output of the present device, if QB and CX are considered input variables and if BY is fixed at the scale factor of unity, i. e. in the preferred embodiment the bush 27 lying on a line parallel to and equidistant from the main guide bars 1 and 2, then In operation, therefore, the multiplicand is the variable QB and the multiplier is the variable CX.

While the device illustrated in Figures 1 and 3 is a combined multiplier and divider, these operations may only be performed separately. For example when a division is required the length CR becomes a variable input and the length QB becomes the output. Thus the variable 4 CR is the dividend and the variable CX in this case is the divisor.

In order that both multiplication and division may be performed simultaneously a third variable is introduced as illustrated in Figures 2 and 4. Instead of the ratiovarying arm being pivoted to the fixed bush 27, it is slidably pivotally connected to the carriage 32 slidably mounted in the longitudinal slot 30 in the second secondary guide bar 29. The slidable carriage 32 thus becomes the point Y and the value BY becomes a variable.

If the length CR is considered the output, and if the lengths QB CX and BY are considered variable inputs, the variable QB may simultaneously be both the multiplicand and the dividend while CX is the multiplier and BY is the divisor.

In both Figures 3 and 4 it will be seen that by extending the lines AB and CD in opposite directions to form the main guide bars 1 and 2, the input variable is capable of changing sign, the length QB representing a positive value when the point Q is on one side of the point B and a negative value when the point Q is on the other side of the point B. Similarly the value of the length CR changes sign correspondingly as the point R passes from one side to the other of the point C.

In practice it has been found that the present device may be constructed to operate with an accuracy of ap proximately 1%, sufiicient for most analog devices. However, because of the extremely high machine tolerances required for such accuracy, the device is best suited to applications where less accuracy is required.

I claim:

1. A combined mechanical multiplier and divider comprising two rigidly held, parallel, main guide members; two main carriages respectively mounted for movement parallel to one another along each of said main guide members; an input drive means serving to cause said movement of one of said main carriages; said movement of the other of said carriages serving to operate an output drive means; a cross guide member rigidly mounted along a straight line crossing both of said main guide members; a variable-ratio, drive-transmitting member extending across both of said main guide members, slidably pivotally connected to each of said main carriages and piv- 5 otally connected to said cross guide member by a pivot member adjustable along the length of said cross guide member; a secondary guide member rigidly mounted along a line crossing both of said main guide members other than the line along which said cross guide member is lying; a secondary carriage mounted for movement along said secondary guide member; a ratio-varying member rigidly connected to said pivot member, slidably pivotally connected to said secondary carriage on one side of said pivot member and pivoted at a point on the other side of said pivot member; and drive means serving to move said secondary carriage along said secondary member.

2. A combined mechanical multiplier and divider comprising two rigidly held, parallel, main guide members; two main carriages respectively mounted for movement parallel to one another along each of said main guide members; an input drive means serving to cause said movement of one of said main carriages; said movement of the other of said carriages serving to operate an output drive means; a cross guide member rigidly mounted along a straight line crossing both of said main guide members; a variable-ratio, drive-transmitting member extending across both of said main guide members, slidably pivotally connected to each of said main carriages and pivotally connected to said cross guide member by a pivot member adjustable along the length of said cross guide member; two parallel secondary guide members rigidly mounted each along a line crossing both of said main guide members, and on either side of the line along which said cross guide member is lying; two secondary carriages respectively mounted for movement parallel to one another along each ofsaid secondary guide members; a ratio-varying member rigidly connected to said pivot member and slidably pivotally connected to each of said secondary carriages; and separate drive means for effecting the movement of each of said secondary carriages along the secondary guide member on which it is mounted.

3. A device as claimed in claim 1 in which the longitudinal axis of said secondary guide member, the longitudinal axis of said cross guide member and the longitudinal axis of one of said main guide members intersect a common line normal to the plane of the longitudinal axis of said main guide members.

4. A device as claimed in claim 3 comprising a band rigidly attached to each of said main carriages, each of said bands being tautly held by and between two pulleys mounted one at each end of the main guide member on which is mounted the main carriage to which the band is attached; a first train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the pulley at one end of one of said main guide members; a second train of gear wheels, one gear wheel of which is mounted co-axially with and rotated by the pulley at one end of the other of said main guide members; a threaded shaft mounted adjacent and parallel to said secondary guide member; an internally threaded collar mounted on and in engagement with the thread of said shaft, said collar being rigidly connected to said secondary carriage; and a third train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate said shaft.

5. A device as claimed in claim 2 in which the longitudinal axis of one of said secondary guide members, th t of said cross guide member and of one of said main guide members intersect a common line normal to the plane of said main guide members, and the longitudinal axis of the other of said secondary guide members, that of said cross guide member and of the other of said main guide members intersect a common line normal to the plane of the longitudinal axis of said main guide members.

6. A device as claimed in claim 5 comprising a band rigidly attached to each of said main carriages, each of said bands being tautly held by and between two pulleys mounted one at each end of the main guide member on which is mounted the main carriage to which the band is attached; a first train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the pulley at one end of one of said main guide members; a second train of gear wheels, one gear wheel of which is mounted co-axially with and rotated by the pulley at one end of the other of said main guide members; a threaded shaft mounted adjacent and parallel to each of said secondary guide members; an internally threaded collar mounted on and in engagement with the thread of each of said shafts, each of said collars being rigidly connected to the secondary carriage on the secondary guide member adjacent the threaded shaft on which the collar is mounted; a third train of gear Wheels, one gear wheel of which is mounted co-axially with and serves to rotate one of said threaded shafts; and a fourth train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the other of said threaded shafts.

7. A combined mechanical multiplier and divider comprising two rigidly held, longitudinally-slotted, parallel, main guide bars; a first and a second carriage respectively mounted for movement parallel to one another in the longitudinal slot formed in each of said main guide bars; an input drive means serving to cause said movement of said first carriage; said movement of said second carriage serving to operate an output drive means; a longitudinally-slotted cross guide bar rigidly mounted along a line normal to and crossing both of said main guide bars; a longitudinally-slotted, variableratio, drive-transmitting bar extending across both of said main guide bars; a third and a fourth carriage slidably mounted in the longitudinal slot in said drivetransmitting bar and being respectively pivotally mounted on said first and said second carriages; said drive-transmitting bar being pivotally connected to a pivot member which is in slidable engagement with the longitudinal slot in said cross guide bar; a longitudinallyslotted, secondary guide bar rigidly mounted along a line, other than that in which said cross guide bar is lying, extending across both of said main guide bars and crossing one of said main guide bars at the same point as does the line along which said cross guide bar is lying; a fifth carriage slidably mounted in the longitudinal slot in said secondary guide bar; a longitudinallyslotted, ratio-varying bar pivotally connected to said pivot member and pivoted at a point on one side of said pivot member; a sixth carriage slidably mounted in the longitudinal slot in said ratio-varying bar on the other side of said pivot member, said sixth carriage being pivotally connected to said fifth carriage; and an input drive means serving to move said fifth carriage along said secondary guide bar.

8. A device as claimed in claim 7 comprising a band rigidly attached to each of said first and said second carriages, each of said bands being tautly held by and between two pulleys mounted one at each end of the main guide bar on which is mounted the carriage to which the band is attached; a first train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the pulley at one end of one of said main guide bars; a second train of gear wheels, one gear Wheel of which is mounted co-axially with and rotated by the pulley at one end of the other of said main guide bars; a threaded shaft mounted adjacent and parallel to said secondary guide bar; an internally threaded collar mounted on and in engagement with the thread of said shaft, said collar being rigidly connected to said fifth carriage; and a third train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate said shaft.

9. A combined mechanical multiplier and divider comprising two rigidly held, longitudinally-slotted, parallel, main guide bars; a first and a second carriage respectively mounted for movement parallel to one another in the longitudinal slot formed in each of said main guide bars; an input drive means serving to cause said movement of said first carriage; said movement of said second carriage serving to operate an output drive means; a longitudinallyslotted, cross guide bar rigidly mounted along a line normal to and crossing both of said main guide bars; a longitudinally-slotted, variableratio, drive-transmitting bar extending across both of said main guide bars; a third and a fourth carriage slidably mounted in the longitudinal slot in said drivetransmitting bar and being respectively pivotally mounted on said first and said second carriages; said drive-transmitting bar being pivotally connected to a pivot member which is in slidable engagement with the longitudinal slot in said cross guide bar; two longitudinally-slotted, parallel, secondary guide bars rigidly mounted each along a line crossing both of said main guide bars and on either side of the line along which said cross guide bar is lying; the line along which one of said secondary guide bars is lying crossing one of said main guide bars at the same point as does the line along which said cross guide bar is lying and the line along which the other of said secondary guide bars is lying crossing the other of said main guide bars at the same point as does the line along which said cross guide bar is lying; a fifth and a sixth carriage slidably mounted for movement parallel one to another, one in the longitudinal slot in each of said secondary guide bars; a longitudinally-slotted, ratio-varying bar pivotally connected to said pivot member; a seventh and an eighth carriage mounted in the longitudinal slot in said ratio-varying bar, one on either side of said pivot member; said seventh carriage being pivotally connected to said fifth carriage; said eighth carriage being pivotally connected 7 to said sixth carriage; and separate input drive means serving to move said seventh carriage and said eighth carriage respectively along said secondary guide bars.

10. A device as claimed in claim 9 comprising a band rigidly attached to each of said first and said second carriages, each of said bands being tautly held by and between two pulleys mounted one at each end of the main guide bar on which is mounted the carriage to which the band is attached; a first train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the pulley at one end of one of said main guide bars; a second train of gear wheels, one gear wheel of which is mounted co-axially with and rotated by the pulley at one end of the other of said main guide bars; a threaded shaft mounted adjacent and parallel to each of said secondary guide bars; an internally threaded collar mounted on and in engagement with the thread of each of said shafts; each of said collars being rigidly connected to the carriage mounted in the longitudinal slot in the secondary guide bar adjacent the threaded shaft on which the collar is mounted; a third train of gear wheels, one gear wheel of which is mounted coaxially with and serves to rotate one of said threaded shafts; and a fourth train of gear wheels, one gear wheel of which is mounted co-axially with and serves to rotate the other of said threaded shafts.

References Cited in the file of this patent UNITED STATES PATENTS 1,279,829 Bell Sept. 24, 1918 FOREIGN PATENTS 729,414 Germany Dec. 16, 1942 255,462 Italy Oct. 24, 1927 

